How healthy and clean was seafood from the Gulf of Mexico before the oil spill?

According to a lot of people I've talked to for stories about the oil spill, demand for Gulf seafood is off. It seems like a lot of people are anxious about the health-worthiness of seafood coming out of the region. But, it's not as if the spilled oil and dispersants are the only contaminants the seafood we eat could encounter.

One way they NOAA tracks pollutants in the water is with a program called "Mussel Watch." They say it's "the longest running continuous contaminant monitoring program in U.S. coastal and Great Lakes waters." In the Gulf of Mexico, the program tests oysters.

I sent NOAA a few questions specific to the Gulf and the contamination in the area before the oil spill. Below, you'll find their answers:

How healthy were Gulf Oysters before the spill? What contaminants did they show?

"Contaminant levels vary across the Gulf Coast Mussel Watch sites. Mussel Watch looks at three general classes of chemicals in Gulf Coast oysters: trace elements, oil related compounds, and chlorinated pesticides. As with the rest of the nation the chlorinated contaminants associated with pesticides such as DDT and industrial chemicals such as PCBs are decreasing. A few sites were elevated for certain trace elements as compared to the Gulf average and generally speaking the Gulf did not exhibit the highest regional concentrations of the oil related compounds. Note, that none of the oysters were found to have been above FDA Action Levels for those organic contaminants for which they test."

Were there any levels of contaminants before the oil spill that were problematic?

"The organic chemical most frequently associated with oil spills are known as the polycyclic aromatic hydrocarbons (PAHs). Certain percentages of PAHs can be found in water and oysters from normal human activities, forest fires, and natural oil seeps. We anticipate a repeat sampling of Mussel Watch sites to occur sometime in the coming months to determine whether increased PAHs concentrations are apparent in oyster populations along the Gulf Coast.
A full report from NOAA's MusselWatch Program contains information on high, medium, and low contamination concentrations. It can be accessed via the site below, with state information broken down on the following pages: Louisiana-78, Alabama-63, Mississippi-84, Florida-72, Texas-96. A regional summary is also available on page 16. http://ccma.nos.noaa.gov/publications/MWTwoDecades.pdf"

Have you done testing at your monitoring sites since the spill?

"Yes, 50 sites from the Brazos River in Texas to our Mussel Watch site in the Florida Keys were sampled. In addition to oysters the field teams also collected sediments and water for chemical characterization. Sediments were also collected in triplicate to characterize the species found there before an oiling event. The species characterization will both determine which species were there as-well-as species specific abundances. That both chemistry and biology were considered as part of the special baseline assessment will help improve our ability to determine the consequences on oiling at any of the Mussel Watch sites."

If so, what sort of results are you getting?

"We do not have any results to report as yet but it will require follow-up sampling and the comparison of the follow-up results to the baseline data to determine what the effect on the environment has been. It takes time for laboratories to analyze the samples and data."